1. Field of the Invention
This invention relates generally to a system and method for assessing the potential for a collision in a vehicle collision avoidance system and/or to plan safety-allowed vehicle trajectories for vehicle path planning and, more particularly, to a system and method for assessing the potential for a collision in a vehicle collision avoidance system and/or to plan safety-allowed vehicle trajectories for vehicle path planning that employs holistic techniques including defining virtual dynamic safety shields around objects in the vicinity of an ego-vehicle and determining whether any of those shields interact with an action grid defined around the ego-vehicle.
2. Discussion of the Related Art
Vehicles are becoming more autonomous or cognitive with the goal being a completely autonomously driven vehicle, i.e., vehicles that are able to provide driving control with minimal or no driver intervention. Adaptive cruise control systems have been available for a number of years where not only does the system maintain a set speed, but also will automatically slow the vehicle down in the event that a slower moving vehicle is detected in front of the subject vehicle. Vehicle control systems currently exist that include autonomous parking where the vehicle will automatically provide the steering control for parking the vehicle. Also, control systems exist that may intervene if the driver makes harsh steering changes that may affect vehicle stability and lane centering capabilities, where the vehicle system attempts to maintain the vehicle near the center of the travel lane. Future vehicles will likely employ autonomous systems for lane changing, passing, turns away from traffic, turns into traffic, merging into traffic, passing through or turning at intersections, etc. As these systems become more prevalent in vehicle technology, it will be necessary to determine what the driver's role will be in combination with these systems for controlling vehicle speed, steering and overriding the autonomous system.
As vehicle technology trends towards more cognitive vehicles those vehicles are becoming better equipped with algorithms and intelligence that allows the vehicle to perform many safety and convenience functions. As sensors and algorithms advance, the amount of data that is available to be processed increases, and algorithms can be devised to use current data and historical data to make decisions concerning safe maneuvers in pre-planned trajectories and vehicle collision avoidance. The ultimate goal for such cognitive vehicles would be a vehicle that is capable of operation and decision making as if it were being driven by a human.
Part of the technology required for vehicle driver autonomy is the ability for vehicles to communicate with each other. Vehicular ad-hoc network (VANET) based active safety and driver assistance systems, such as a dedicated short range communications (DSRC) system, known to those skilled in the art, allow a vehicle to transmit messages to other vehicles in a particular area with warning messages about dangerous road conditions, driving events, accidents, etc. In these systems, either direct broadcast communications or multi-hop geocast routing protocols, known to those skilled in the art, are commonly used to communicate warning messages, i.e., to deliver messages to vehicles that are within direct communication range or are located within a few kilometers from the road condition. In other words, an initial message advising drivers of a potential hazardous condition is transmitted from vehicle to vehicle either in a direct broadcast fashion or by using a geocast routing protocol so that vehicles within the desired application range will receive the messages of interest.
The communications systems referred to above include vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) applications that require a minimum of one entity to send information to another entity. For example, many vehicle-to-vehicle safety applications can be executed on one vehicle by simply receiving broadcast messages from one or more neighboring vehicles. These messages are not directed to any specific vehicle, but are meant to be shared with a vehicle population to support the safety application. In these types of applications where collision avoidance is desirable, as two or more vehicles talk to one another and a collision becomes probable, the vehicle systems can warn the vehicle drivers, or possibly take action for the driver, such as applying the brakes. Likewise, roadway infrastructure components, such as traffic control units, can observe the information broadcasts or otherwise sense vehicle traffic and provide a driver warning if there is a detected hazard (e.g., if a vehicle is approaching a curve at an unsafe speed or there is a crossing vehicle that is violating a red traffic signal phase).
Vehicle driving control autonomy is only as good as the ability of sensors on the vehicle to reliably detect and track objects around the vehicle. Many modern vehicles include object detection sensors that are used to enable collision warning or avoidance and other active safety applications. The object detection sensors may use any of a number of sensing technologies, such as short range radar, cameras with image processing, laser or LiDAR, ultrasound, etc. The object detection sensors detect vehicles and other objects in the path of a subject vehicle, and the application software uses the object detection information to provide warnings or take actions as appropriate. In many vehicles, the object detection sensors are integrated directly into the front or other fascia of the vehicle.
Current vehicle lane sensing systems typically use vision systems to sense the vehicle travel lane and drive the vehicle in the lane-center. Many of these known lane sensing systems detect lane-markers on the road for various applications, such as lane departure warning (LDW), lane keeping (LK), lane centering (LC), etc., and have typically employed a single camera, either at the front or rear of the vehicle, to provide the images that are used to detect the lane-markers.